Carrier determination for a device

ABSTRACT

Apparatuses, methods, and systems are disclosed for carrier determination. One apparatus includes a processor that determines a first carrier of multiple carriers for a first device to transmit control information. The apparatus also includes a transmitter that transmits, to the first device, a first physical control signal indicating the first carrier, wherein the first physical control signal further indicates an interlace index for transmitting control information. The apparatus includes a receiver that receives control information from the first device on the first carrier.

FIELD

The subject matter disclosed herein relates generally to wirelesscommunications and more particularly relates to carrier determinationfor a device in a wireless communication system.

BACKGROUND

The following abbreviations are herewith defined, at least some of whichare referred to within the following description.

3GPP Third Generation Partnership Project

ACK Positive-Acknowledgment

ANDSF Access Network Discovery and Selection Function

AP Access Point

APN Access Point Name

AS Access Stratum

B-IFDMA Block Interleaved Frequency Division Multiple Access

BLER Block Error Ratio

BPSK Binary Phase Shift Keying

CAZAC Constant Amplitude Zero Auto Correction

CCA Clear Channel Assessment

CCE Control Channel Element

CP Cyclic Prefix

CQI Channel Quality Information

CSI Channel State Information

CRS Cell-Specific Reference Signal

CSS Common Search Space

DCI Downlink Control Information

DL Downlink

DFT Discrete Fourier Transform

DMRS Demodulation Reference Signal

EDGE Enhanced Data Rates for Global Evolution

eNB Evolved Node B

EPDCCH Enhanced Physical Downlink Control Channel

E-RAB E-UTRAN Radio Access Bearer

ETSI European Telecommunications Standards Institute

E-UTRAN Evolved Universal Terrestrial Radio Access Network

FBE Frame Based Equipment

FDD Frequency Division Duplex

FDMA Frequency Division Multiple Access

FEC Forward Error Correction

GERAN GSM/EDGE Radio Access Network

GPRS General Packet Radio Service

GSM Global System for Mobile Communication

GTP GPRS Tunneling Protocol

HARQ Hybrid Automatic Repeat Request

H-PLMN Home Public Land Mobile Network

IFDMA Interleaved Frequency Division Multiple Access

IoT Internet-of-Things

IP Internet Protocol

ISRP Inter-System Routing Policy

LAA Licensed Assisted Access

LBE Load Based Equipment

LBT Listen-Before-Talk

LTE Long Term Evolution

MCL Minimum Coupling Loss

MCS Modulation and Coding Scheme

MME Mobility Management Entity

MU-MIMO Multi-User, Multiple-Input, Multiple-Output

NACK or NAK Negative-Acknowledgment

NAS Non-Access Stratum

NBIFOM Network-Based IP Flow Mobility

NB-IoT NarrowBand Internet of Things

OFDM Orthogonal Frequency Division Multiplexing

PCell Primary Cell

PBCH Physical Broadcast Channel

POD Physical Cell Identification (“ID”)

PCO Protocol Configuration Options

PCRF Policy and Charging Rules Function

PDCCH Physical Downlink Control Channel

PDCP Packet Data Convergence Protocol

PDN Packet Data Network

PDSCH Physical Downlink Shared Channel

PDU Protocol Data Unit

PGW Packet Data Network Gateway

PHICH Physical Hybrid ARQ Indicator Channel

PLMN Public Land Mobile Network

PRACH Physical Random Access Channel

PRB Physical Resource Block

PSD Power Spectrum Density

PSS Primary Synchronization Signal

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

QoS Quality of Service

QPSK Quadrature Phase Shift Keying

RAB Radio Access Bearer

RAN Radio Access Network

RAR Random Access Response

RE Resource Element

RRC Radio Resource Control

RS Reference Signal

RX Receive

SC-FDMA Single Carrier Frequency Division Multiple Access

SCell Secondary Cell

SCH Shared Channel

SGW Serving Gateway

SIB System Information Block

SINR Signal-to-Interference-Plus-Noise Ratio

SR Scheduling Request

SSS Secondary Synchronization Signal

TAU Tracking Area Update

TBS Transport Block Size

TCP Transmission Control Protocol

TDD Time-Division Duplex

TDM Time Division Multiplex

TEID Tunnel Endpoint Identification (“ID”)

TTI Transmit Time Interval

TX Transmit

UCI Uplink Control Information

UE User Entity/Equipment (Mobile Terminal)

UL Uplink

UMTS Universal Mobile Telecommunications System

V-PLMN Visited Public Land Mobile Network

WiMAX Worldwide Interoperability for Microwave Access

WLAN Wireless Local Area Network

In wireless communications networks, a frame structure for LTE FDD maybe used. A radio frame of 10 milliseconds (“ms”) may include 10subframes, each of which is 1 ms. Each subframe further may include twoslots, each of which is 0.5 ms. Within each slot, a number of OFDMsymbols may be transmitted. The transmitted signal in each slot on anantenna port may be described by a resource grid comprising N_(RB)^(UL)N_(sc) ^(RB) subcarriers and N_(symb) ^(UL) OFDM symbols, whereN_(RB) ^(UL) is a number of RBs in the UL (which is dependent on thetransmission bandwidth of a cell); N_(sc) ^(RB) is the number ofsubcarriers in each RB; and each subcarrier occupies a certain frequencyof size Δf. The values of N_(sc) ^(RB), Δf, and N_(symb) ^(UL) maydepend on a cyclic prefix as shown in Table 1.

TABLE 1 Configuration N_(sc) ^(RB) N_(symb) ^(UL) Normal Cyclic PrefixΔf = 15 kHz 12 7 Extended Cyclic Prefix Δf = 15 kHz 6 Δf = 7.5 kHz 24 3

In certain configurations, an antenna port may refer to a logicalantenna port (i.e., it may not necessarily refer to a physical antennaor antenna element). Mapping between an antenna port and physicalantenna element(s) may be implementation specific. In other words,different devices may have a different mapping of physical antennaelement(s) to the same antenna port. A receiving device may assume thatthe signals transmitted on the same antenna port go through the samechannel. Moreover, a receiving device cannot assume signals transmittedon different antenna ports go through the same channel.

In certain wireless communication networks, an unlicensed spectrum mayinclude operational requirements, such as an occupied bandwidthrequirement, and a power spectrum density (“PSD”) requirement. In onewireless communication network, a nominal channel bandwidth is thewidest band of frequencies (including guard bands) assigned to a singlechannel. In certain networks, the nominal channel bandwidth should be atleast 5 MHz. In various networks, an occupied channel bandwidth (e.g.,the bandwidth containing 99% of the power of the signal) should bebetween 80% and 100% of the nominal channel bandwidth. In some networks,a maximum PSD is 10 dBm/MHz in ETSI with a resolution bandwidth of 1MHz. Such a maximum PSD implies that a signal which occupies a smallportion of the bandwidth may not be transmitted at the maximum availablepower at a UE due to the PSD and occupied bandwidth constraints. In somewireless communication networks, B-IFDMA based waveforms may be used forLAA PUCCH transmission. In such networks, transmissions may beinefficient.

BRIEF SUMMARY

Apparatuses for carrier determination are disclosed. Methods and systemsalso perform the functions of the apparatus. In one embodiment, theapparatus includes a processor that determines a first carrier ofmultiple carriers for a first device to transmit control information. Incertain embodiments, the apparatus includes a transmitter thattransmits, to the first device, a first physical control signalindicating the first carrier and wherein the first physical controlsignal further indicates an interlace index for transmitting controlinformation. In some embodiments, the apparatus includes a receiver thatreceives control information from the first device on the first carrier.

In certain embodiments, the first physical control signal furtherindicates an interlace index to the first device. In some embodiments,the first physical control signal further indicates an orthogonal coversequence index to the first device. In one embodiment, the processordetermines a control channel for the first device. The control channelmay be defined by at least one of an interlace index and an orthogonalcover sequence index. In such an embodiment, the transmitter transmits,to the first device, a second physical control signal indicating thecontrol channel and the receiver receives control information from thefirst device using the control channel. In various embodiments, thetransmitter transmits the first physical control signal to a seconddevice, and the receiver receives control information from the seconddevice on the first carrier. In some embodiments, the processordetermines a time for the first device to transmit control information,the transmitter transmits, to the first device, a third physical controlsignal indicating the determined time, and the receiver receives controlinformation from the first device during the determined time. In certainembodiments, the transmitter transmits the third physical control signalto a second device, and the receiver receives control information fromthe second device during the determined time. In some embodiments, thethird physical control signal indicates a delay after the end of atransmission burst.

In certain embodiments, the processor determines a random backoffcounter for the first device, and the transmitter transmits, to thefirst device, a fourth physical control signal indicating the randombackoff counter. In various embodiments, the transmitter transmits, to asecond device, the fourth physical control signal. In some embodiments,the processor determines the first carrier based on at least one of aload condition and an interference condition on the multiple carriers.

One method for carrier determination includes determining a firstcarrier of multiple carriers for a first device to transmit controlinformation. The method also includes transmitting, to the first device,a first physical control signal indicating the first carrier. In certainembodiments, the method includes receiving control information from thefirst device on the first carrier.

Another apparatus for carrier determination includes a receiver thatreceives a first physical control signal indicating a first carrier ofmultiple carriers for transmitting control information. In certainembodiments, the apparatus includes a transmitter that transmits controlinformation on the first carrier.

In some embodiments, the first physical control signal further indicatesan interlace index for transmitting control information. In variousembodiments, the first physical control signal further indicates anorthogonal cover sequence index for transmitting control information. Insome embodiments, the receiver receives a second physical control signalindicating a control channel. The control channel may be defined by atleast one of an interlace index and an orthogonal cover sequence index.In such embodiments, the transmitter transmits control information usingthe control channel. In certain embodiments, the receiver receives athird physical control signal indicating a time, and the transmittertransmits control information during the time.

In some embodiments, the third physical control signal indicates a delayafter the end of a transmission burst. In certain embodiments, theapparatus includes a processor, the receiver receives a fourth physicalcontrol signal indicating a random backoff counter, and the processorperforms listen-before-talk (“LBT”) using the random backoff counter onthe first carrier.

Another method for carrier determination includes receiving a firstphysical control signal indicating a first carrier of multiple carriersfor transmitting control information. In certain embodiments, the methodincludes transmitting control information on the first carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described abovewill be rendered by reference to specific embodiments that areillustrated in the appended drawings. Understanding that these drawingsdepict only some embodiments and are not therefore to be considered tobe limiting of scope, the embodiments will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of awireless communication system for carrier determination;

FIG. 2 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for carrier determination;

FIG. 3 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for carrier determination;

FIG. 4 illustrates one embodiment of carrier transmissions;

FIG. 5 illustrates one embodiment of a channel structure formultiplexing control information;

FIG. 6 illustrates another embodiment of a channel structure formultiplexing control information;

FIG. 7 illustrates a further embodiment of a channel structure formultiplexing control information;

FIG. 8 is a schematic flow chart diagram illustrating one embodiment ofa method for carrier determination; and

FIG. 9 is a schematic flow chart diagram illustrating another embodimentof a method for carrier determination.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of theembodiments may be embodied as a system, apparatus, method, or programproduct. Accordingly, embodiments may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,embodiments may take the form of a program product embodied in one ormore computer readable storage devices storing machine readable code,computer readable code, and/or program code, referred hereafter as code.The storage devices may be tangible, non-transitory, and/ornon-transmission. The storage devices may not embody signals. In acertain embodiment, the storage devices only employ signals foraccessing code.

Certain of the functional units described in this specification may belabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom very-large-scale integration(“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such aslogic chips, transistors, or other discrete components. A module mayalso be implemented in programmable hardware devices such as fieldprogrammable gate arrays, programmable array logic, programmable logicdevices or the like.

Modules may also be implemented in code and/or software for execution byvarious types of processors. An identified module of code may, forinstance, include one or more physical or logical blocks of executablecode which may, for instance, be organized as an object, procedure, orfunction. Nevertheless, the executables of an identified module need notbe physically located together, but may include disparate instructionsstored in different locations which, when joined logically together,include the module and achieve the stated purpose for the module.

Indeed, a module of code may be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different computer readable storage devices.Where a module or portions of a module are implemented in software, thesoftware portions are stored on one or more computer readable storagedevices.

Any combination of one or more computer readable medium may be utilized.The computer readable medium may be a computer readable storage medium.The computer readable storage medium may be a storage device storing thecode. The storage device may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage devicewould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), a portable compact disc read-onlymemory (“CD-ROM”), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number oflines and may be written in any combination of one or more programminglanguages including an object oriented programming language such asPython, Ruby, Java, Smalltalk, C++, or the like, and conventionalprocedural programming languages, such as the “C” programming language,or the like, and/or machine languages such as assembly languages. Thecode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (“LAN”) or a wide area network (“WAN”), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“having,” and variations thereof mean “including but not limited to,”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusive,unless expressly specified otherwise. The terms “a,” “an,” and “the”also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

Aspects of the embodiments are described below with reference toschematic flowchart diagrams and/or schematic block diagrams of methods,apparatuses, systems, and program products according to embodiments. Itwill be understood that each block of the schematic flowchart diagramsand/or schematic block diagrams, and combinations of blocks in theschematic flowchart diagrams and/or schematic block diagrams, can beimplemented by code. These code may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the schematic flowchartdiagrams and/or schematic block diagrams block or blocks.

The code may also be stored in a storage device that can direct acomputer, other programmable data processing apparatus, or other devicesto function in a particular manner, such that the instructions stored inthe storage device produce an article of manufacture includinginstructions which implement the function/act specified in the schematicflowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus orother devices to produce a computer implemented process such that thecode which execute on the computer or other programmable apparatusprovide processes for implementing the functions/acts specified in theflowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations of apparatuses, systems, methods and programproducts according to various embodiments. In this regard, each block inthe schematic flowchart diagrams and/or schematic block diagrams mayrepresent a module, segment, or portion of code, which includes one ormore executable instructions of the code for implementing the specifiedlogical function(s).

It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. Other steps and methods may be conceived that are equivalentin function, logic, or effect to one or more blocks, or portionsthereof, of the illustrated Figures.

Although various arrow types and line types may be employed in theflowchart and/or block diagrams, they are understood not to limit thescope of the corresponding embodiments. Indeed, some arrows or otherconnectors may be used to indicate only the logical flow of the depictedembodiment. For instance, an arrow may indicate a waiting or monitoringperiod of unspecified duration between enumerated steps of the depictedembodiment. It will also be noted that each block of the block diagramsand/or flowchart diagrams, and combinations of blocks in the blockdiagrams and/or flowchart diagrams, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and code.

The description of elements in each figure may refer to elements ofproceeding figures. Like numbers refer to like elements in all figures,including alternate embodiments of like elements.

FIG. 1 depicts an embodiment of a wireless communication system 100 forcarrier determination. In one embodiment, the wireless communicationsystem 100 includes remote units 102 and base units 104. Even though aspecific number of remote units 102 and base units 104 are depicted inFIG. 1, one of skill in the art will recognize that any number of remoteunits 102 and base units 104 may be included in the wirelesscommunication system 100.

In one embodiment, the remote units 102 may include computing devices,such as desktop computers, laptop computers, personal digital assistants(“PDAs”), tablet computers, smart phones, smart televisions (e.g.,televisions connected to the Internet), set-top boxes, game consoles,security systems (including security cameras), vehicle on-boardcomputers, network devices (e.g., routers, switches, modems), lowthroughput devices, low delay sensitivity devices, ultra-low costdevices, low power consumption devices, an IoT device, or the like. Insome embodiments, the remote units 102 include wearable devices, such assmart watches, fitness bands, optical head-mounted displays, or thelike. Moreover, the remote units 102 may be referred to as subscriberunits, mobiles, mobile stations, users, terminals, mobile terminals,fixed terminals, subscriber stations, UE, user terminals, a device, orby other terminology used in the art. The remote units 102 maycommunicate directly with one or more of the base units 104 via ULcommunication signals.

The base units 104 may be distributed over a geographic region. Incertain embodiments, a base unit 104 may also be referred to as anaccess point, an access terminal, a base, a base station, a Node-B, aneNB, a Home Node-B, a relay node, a device, or by any other terminologyused in the art. The base units 104 are generally part of a radio accessnetwork that may include one or more controllers communicably coupled toone or more corresponding base units 104. The radio access network isgenerally communicably coupled to one or more core networks, which maybe coupled to other networks, like the Internet and public switchedtelephone networks, among other networks. These and other elements ofradio access and core networks are not illustrated but are well knowngenerally by those having ordinary skill in the art. For example, one ormore base units 104 may be communicably coupled to an MME, an SGW,and/or a PGW.

In one implementation, the wireless communication system 100 iscompliant with the LTE of the 3GPP protocol, wherein the base unit 104transmits using an OFDM modulation scheme on the DL and the remote units102 transmit on the UL using a SC-FDMA scheme. In anotherimplementation, the remote units 102 transmit on the UL using a B-IFDMAscheme when it is operated on unlicensed spectrum. In B-IFDMA, theminimum transmission unit is one interlace, which is a set of RBsuniformly spaced in frequency and has a frequency span that exceeds apredetermined percent of the system bandwidth. For a 20 MHz systembandwidth with 100 PRBs, if it is divided into 10 interlaces, then thek^(th) interlace is composed of the PRBs {k, k+10, k+20, . . . , k+90}and the (k+1)^(th) interlace is composed of the PRBs {k+1, k+11, k+21, .. . , k+91}, 0<=k<=9. In another implementation, the wirelesscommunication system 100 is compliant with NB-IoT. More generally,however, the wireless communication system 100 may implement some otheropen or proprietary communication protocol, for example, WiMAX, amongother protocols. The present disclosure is not intended to be limited tothe implementation of any particular wireless communication systemarchitecture or protocol.

The base units 104 may serve a number of remote units 102 within aserving area, for example, a cell or a cell sector via a wirelesscommunication link. The base units 104 transmit DL communication signalsto serve the remote units 102 in the time, frequency, and/or spatialdomain.

In one embodiment, an apparatus (e.g., base unit 102) may determine afirst carrier of multiple carriers for a first device to transmitcontrol information. In some embodiments, the apparatus may determinethe first carrier based on at least one of a load condition and aninterference condition on the multiple carriers. In certain embodiments,the apparatus may transmit, to the first device, a first physicalcontrol signal indicating the first carrier. In various embodiments, thefirst physical control signal further indicates an interlace index tothe first device. In some embodiments, the first physical control signalfurther indicates an orthogonal cover sequence index to the firstdevice. In certain embodiments, the apparatus may determine a time forthe first device to transmit control information, transmit, to the firstdevice, a third physical control signal indicating the determined time,and receive control information from the first device during thedetermined time. In some embodiments, the third physical control signalmay indicate a delay after the end of a transmission burst. In certainembodiments, the apparatus may determine a random backoff counter forthe first device, and transmit, to the first device, a fourth physicalcontrol signal indicating the random backoff counter. In someembodiments, the apparatus may receive control information from thefirst device on the first carrier. Therefore, the base unit 104 maydetermine a carrier to be used by the first device and other devices.

In a further embodiment, an apparatus (e.g., remote unit 104 ) mayreceive a first physical control signal indicating a first carrier ofmultiple carriers for transmitting control information. In someembodiments, the first physical control signal further indicates aninterlace index for transmitting control information. In variousembodiments, the first physical control signal further indicates anorthogonal cover sequence index for transmitting control information. Incertain embodiments, the apparatus receives a third physical controlsignal indicating a time, and transmits control information during thetime. In some embodiments, the third physical control signal indicates adelay after the end of a transmission burst. In certain embodiments, theapparatus may receive a fourth physical control signal indicating arandom backoff counter, and perform LBT using the random backoff counteron the first carrier. The apparatus may also transmit controlinformation on the first carrier.

FIG. 2 depicts one embodiment of an apparatus 200 that may be used forcarrier determination. The apparatus 200 includes one embodiment of theremote unit 102. Furthermore, the remote unit 102 may include aprocessor 202, a memory 204, an input device 206, a display 208, atransmitter 210, and a receiver 212. In some embodiments, the inputdevice 206 and the display 208 are combined into a single device, suchas a touchscreen. In certain embodiments, the remote unit 102 may notinclude any input device 206 and/or display 208. In various embodiments,the remote unit 102 may include one or more of the processor 202, thememory 204, the transmitter 210, and the receiver 212, and may notinclude the input device 206 and/or the display 208.

The processor 202, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 202 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 202 executes instructions stored in thememory 204 to perform the methods and routines described herein. Theprocessor 202 is communicatively coupled to the memory 204, the inputdevice 206, the display 208, the transmitter 210, and the receiver 212.In certain embodiments, the processor 202 may perform an LBT.

The memory 204, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 204 includes volatile computerstorage media. For example, the memory 204 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 204 includes non-volatilecomputer storage media. For example, the memory 204 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 204 includes bothvolatile and non-volatile computer storage media. In some embodiments,the memory 204 stores data relating to an indication to be provided toanother device. In some embodiments, the memory 204 also stores programcode and related data, such as an operating system or other controlleralgorithms operating on the remote unit 102.

The input device 206, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 206 maybe integrated with the display 208, for example, as a touchscreen orsimilar touch-sensitive display. In some embodiments, the input device206 includes a touchscreen such that text may be input using a virtualkeyboard displayed on the touchscreen and/or by handwriting on thetouchscreen. In some embodiments, the input device 206 includes two ormore different devices, such as a keyboard and a touch panel.

The display 208, in one embodiment, may include any known electronicallycontrollable display or display device. The display 208 may be designedto output visual, audible, and/or haptic signals. In some embodiments,the display 208 includes an electronic display capable of outputtingvisual data to a user. For example, the display 208 may include, but isnot limited to, an LCD display, an LED display, an OLED display, aprojector, or similar display device capable of outputting images, text,or the like to a user. As another, non-limiting, example, the display208 may include a wearable display such as a smart watch, smart glasses,a heads-up display, or the like. Further, the display 208 may be acomponent of a smart phone, a personal digital assistant, a television,a table computer, a notebook (laptop) computer, a personal computer, avehicle dashboard, or the like.

In certain embodiments, the display 208 includes one or more speakersfor producing sound. For example, the display 208 may produce an audiblealert or notification (e.g., a beep or chime). In some embodiments, thedisplay 208 includes one or more haptic devices for producingvibrations, motion, or other haptic feedback. In some embodiments, allor portions of the display 208 may be integrated with the input device206. For example, the input device 206 and display 208 may form atouchscreen or similar touch-sensitive display. In other embodiments,the display 208 may be located near the input device 206.

The transmitter 210 is used to provide UL communication signals to thebase unit 104 and the receiver 212 is used to receive DL communicationsignals from the base unit 104. In some embodiments, the receiver 212 isused to receive a first physical control signal indicating a firstcarrier of multiple carriers for transmitting control information. Inone embodiment, the transmitter 210 is used to transmit data, feedbackinformation, and/or an indication to the base unit 104. In certainembodiments, the transmitter 210 is used to transmit control informationon the first carrier. Although only one transmitter 210 and one receiver212 are illustrated, the remote unit 102 may have any suitable number oftransmitters 210 and receivers 212. The transmitter 210 and the receiver212 may be any suitable type of transmitters and receivers. In oneembodiment, the transmitter 210 and the receiver 212 may be part of atransceiver.

FIG. 3 depicts one embodiment of an apparatus 300 that may be used forcarrier determination. The apparatus 300 includes one embodiment of thebase unit 104. Furthermore, the base unit 104 may include a processor302, a memory 304, an input device 306, a display 308, a transmitter310, and a receiver 312. It should be noted that the processor 302, thememory 304, the input device 306, and the display 308 may besubstantially similar to the processor 202, the memory 204, the inputdevice 206, and the display 208 of the remote unit 102, respectively. Incertain embodiments, the processor 302 may be used to determine a firstcarrier of multiple carriers for a first device to transmit controlinformation.

The transmitter 310 is used to provide DL communication signals to theremote unit 102 and the receiver 312 is used to receive UL communicationsignals from the remote unit 102. In certain embodiments, thetransmitter 310 is used to transmit, to the first device, a firstphysical control signal indicating the first carrier. In one embodiment,the receiver 312 may be used to receive control information from thefirst device on the first carrier. It should be noted that, in certainembodiments, an MME, an SGW, and/or a PGW may include one or morecomponents found in the base unit 104. Furthermore, in certainembodiments, the base unit 104 may represent one embodiment of an MME,an SWG or a PGW.

FIG. 4 illustrates one embodiment of carrier transmissions 400. Theillustrated carrier transmissions 400 include transmissions on a firstcarrier 402 and transmissions on a second carrier 404. It should benoted that the first carrier 402 and/or the second carrier 404 may belicensed or unlicensed carriers. In some embodiments, PUCCH transmissionin the UL on an unlicensed carrier is used. The first carrier 402includes DL transmissions from a base unit 104 in subframes 0 through7—labeled with “D.” The DL transmissions in subframes 0 through 7 may beconsidered one DL burst or one transmission burst. It should be notedthat a DL burst or a transmission burst may refer to informationtransmitted in consecutive subframes. The DL burst includes one or morephysical control signals 406. In one embodiment, the one or morephysical control signals 406 may include information in a common DCIformat 1C. In certain embodiments, the one or more physical controlsignals 406 may include information indicating a carrier of multiplecarriers for a device to transmit control information, an interlaceindex for the device, and/or an orthogonal cover sequence index for thedevice. In various embodiments, the one or more physical control signals406 may include information indicating a control channel for the device(e.g., at least one of an interlace index and an orthogonal coversequence index), a time for the device to transmit control information(e.g., such as an indication of a delay after an end of the DL burst),and/or a random backoff counter (the random backoff counter may be usedto perform LBT). In certain embodiments, the one or more physicalcontrol signals 406 may be transmitted in remote unit-specific searchspace for indicating remote unit-specific information.

In one embodiment, a delay 408 is indicated in the one or more physicalcontrol signals 406 that delays transmission of control information fora period of time after the end of the DL burst. In another embodiment,the delay 408 may be preconfigured. In the illustrated embodiment, thefirst carrier 402 is indicated by the one or more physical controlsignals 406 as the carrier to be used to transmit control information.Accordingly, an LBT 410 is performed before UL control information istransmitted in subframe 1—labeled “U.”

The second carrier 404 includes DL transmissions from the base unit 104in subframes 0 through 5—labeled with “D.” The DL transmissions insubframes 0 through 5 may be considered one DL burst or one transmissionburst. The DL burst includes one or more physical control signals 412.In one embodiment, the one or more physical control signals 412 mayinclude information in a common DCI format 1C. In certain embodiments,the one or more physical control signals 412 may include informationindicating a carrier of multiple carriers for a device to transmitcontrol information, an interlace index for the device, and/or anorthogonal cover sequence index for the device. In various embodiments,the one or more physical control signals 412 may include informationindicating a control channel for the device (e.g., at least one of aninterlace index and an orthogonal cover sequence index), a time for thedevice to transmit control information (e.g., such as an indication of adelay after an end of the DL burst), and/or a random backoff counter(the random backoff counter may be used to perform LBT). In certainembodiments, the one or more physical control signals 406 may betransmitted in remote unit-specific search space for indicating remoteunit-specific information.

In one embodiment, a delay 414 is indicated in the one or more physicalcontrol signals 412 that delays transmission of control information fora period of time after the end of the DL burst. In another embodiment,the delay 414 may be preconfigured. In the illustrated embodiment, thefirst carrier 402 is indicated by the one or more physical controlsignals 412 as the carrier to be used to transmit control information.

In certain embodiments, the one or more physical control signals 406 and412 may indicate an interlace for multiple remote units 102 to transmitUL information. For example, to improve utilization efficiency ofB-IFDMA based PUCCH transmissions, for DL multi-carrier operation on anunlicensed spectrum, HARQ-ACK bits for DL bursts on multiple unlicensedcarriers may be transmitted in one interlace for PUCCH transmission. Inone embodiment, for each unlicensed carrier carrying DL burst andsharing the same interlace for PUCCH transmission, a carrier index forthe unlicensed carrier using for PUCCH transmission may be indicated bythe one or more physical control signals 406 and 412, such as by beingindicated in the common DCI format 1C for DL burst in an end subframe.In certain embodiments, a base unit 104 may determine the carrier to useand/or the carrier index corresponding to the carrier to use.Accordingly, the base unit 104 may dynamically balance the load of UCIon one carrier and/or quickly select one unlicensed carrier with a bestchannel condition or least amount of interference (this may be based onan RSSI measurement reported by a remote unit 102). Thus, for a DL bursttransmission on the first carrier 402 and a DL burst transmission on thesecond carrier 404, all of the remote units 102 scheduled in the DLburst on the first carrier 402 may share one interlace with all of theremote units 102 scheduled in the DL burst on the second carrier 404.The shared interlace may be used for HARQ-ACK transmission. If the firstcarrier 402 is selected by the base unit 104 for PUCCH transmission dueto better channel condition than the second carrier 404, a carrier indexcorresponding to the first carrier 402 may be indicated in the one ormore physical control signals 406 and 412. In another embodiment, thecarrier index corresponding to the first carrier 402 may be indicated inDL grant signaling associated with PDSCH to each remote unit 102.

In some embodiments, the one or more physical control signals 406 and412 may indicate an interlace that is shared by multiple remote units102. In one embodiment, the interlace may be explicitly indicated in theone or more physical control signals 406 and 412 using a concreteinterlace number and/or an index. In certain embodiments, a remote unit102 may be preconfigured to establish a link between a number of OFDMsymbols in a DL burst end subframe with an interlace number and/orindex. For example, in one embodiment, an interlace number may equal anumber of OFDM symbols in the DL burst end subframe mod a number ofinterlaces per UL subframe. In certain embodiments, for DLmulti-carriers sharing one interlace for PUCCH transmission, the baseunit 104 may make an end subframe configuration the same for DL burstson those carriers.

In certain embodiments, the one or more physical control signals 406 and412 may indicate an orthogonal cover sequence index for each remote unit102 to use. It should be noted that after a remote unit 102 haddetermined an interlace and an orthogonal cover sequence index for PUCCHtransmission, the remote unit 102 may transmit the PUCCH on thedetermined PUCCH resource. In this way, a base unit 104 may flexiblyassign the PUCCH resource for one remote unit 102.

In various embodiments, the one or more physical control signals 406 and412 may explicitly indicate a concrete exact orthogonal cover sequenceindex for PUCCH transmission in the DL grant for each remote unit 102.In such embodiments, two bits may be used to support four-remote unit102 multiplexing and three bits may be used to support eight-remote unit102 multiplexing.

In some embodiments, a remote unit 102 may be preconfigured to establisha link between a lowest CCE index for DL grant DCI transmission with anorthogonal cover sequence index for PUCCH transmission. For example, inone embodiment, an orthogonal cover sequence index may correspond to alowest CCE index for DL grant DCI transmission mod a number oforthogonal cover sequences.

In some embodiments, the one or more physical control signals 406 and412 may indicate a time for a remote unit 102 to transmit controlinformation. In one embodiment, the time for transmission of controlinformation may be indicated using a common indicator for multipleremote units 102. For example, in an embodiment in which a DL burst anda corresponding HARQ-ACK are transmitted in different carriers, thesubframe timing info (e.g., subframe offset between the end subframe ofthe DL burst on one unlicensed carrier and the subframe for PUCCHtransmission on another unlicensed carrier) may be indicated in thecommon DCI format 1C on each unlicensed carrier that DL burst istransmitted on.

For example, assuming PUCCH is transmitted in the first carrier 402, asillustrated, the subframe offset (e.g., delay 408) between the endsubframe of the DL burst of the first carrier 402 and the subframe forPUCCH transmission may be indicated in common DCI format 1C for the DLburst of the first carrier 402 (e.g., in the one or more physicalcontrol signals 406). Furthermore, the subframe offset (e.g., delay 414)between the end subframe of DL burst of the second carrier 404 and thesubframe for PUCCH transmission may be indicated in common DCI format 1Cfor the DL burst of the second carrier 404 (e.g., in the one or morephysical control signals 412). It should be noted that the two offsetvalues (e.g., delay 408 and delay 414) may be different. In someembodiments, the base unit 104 may indicate different offset values sothat the same subframe for is used for PUCCH transmission.

In various embodiments, a concrete subframe offset between a current DLsubframe and a subframe for PUCCH transmission is indicated in DL grantfor one remote unit 102 when the associated PDSCH is scheduled in a DLsubframe. In this way, a base unit 104 may flexibly assign the PUCCHtransmission for one remote unit 102 and flexibly multiplex severalremote units' PUCCH in one interlace.

In some embodiments, the one or more physical control signals 406 and412 may indicate a random backoff counter to be used for LBT. LBT isperformed before PUCCH transmission on an unlicensed carrier. Moreover,a subframe carrying PUCCH on a carrier may be a single burst only forPUCCH transmission or a subframe of an UL burst supporting PUCCH andPUSCH multiplexed in one subframe. For PUCCH transmission, one-shot CCAof at least 25 us or LBT category 4 may be used with smaller contentionwindow size compared to PUSCH transmission.

To enable multiple remote units' PUCCH and PUSCH to be multiplexed inone subframe, a base unit 104 may generate a common random backoffcounter and indicate the detailed value of the random backoff counter inthe common DCI format 1C on the DL burst for PUCCH transmission (e.g.,the one or more physical control signals 406 and 412) and indicate thesame value in the UL grant for scheduled PUSCH transmission. In thisway, a remote unit 102 may know the concrete time domain and frequencydomain position for PUCCH transmission. For example, for LBT in 410,using the random backoff counter as an initial count, the initial countmay be counted down by subtracting 1 if the first carrier 402 in oneECCA slot is regarded as idle by energy check, e.g., the received energydoes not exceed a predefined threshold; if the first carrier 402 in oneECCA slot is regarded as busy by energy check, the count may be notcounted down and next ECCA check can be performed until the channelkeeps idle for a predefined period of time. When the count is counteddown to zero, the LBT procedure is finished and the remote unit 102 maystart control information transmission on the first carrier 402. Asdescribed herein, utilization efficiency of an interlace of one PUCCHmay be improved.

As used herein, an interlace may include multiple PRBs. Furthermore,each PRB of an interlace may be uniformly spaced in frequency.Furthermore, the PRBs of an interlace are separated by substantiallyequal (e.g., similar) frequencies. For a given system bandwidth,assuming there are X PRBs {0, 1, . . . , −1} available to be equallydivided to Y interlaces {0, 1, . . . , Y−1}, then each interlace iscomposed of X/Y PRBs and has a frequency span that exceeds apredetermined percent of the system bandwidth. So the k^(th) interlaceis composed of the PRBs {k, k+Y, k+2Y, . . . , k+(X/Y−1)Y} and the(k+1)^(th) interlace is composed of the PRBs {k+1, k+1+Y, k+1+2Y, . . ., k+1+(X/Y−1)Y}, where, 0<=k<=Y−1. Then the two interlaces, the(k+1)^(th) interlace and the k^(th) interlace, are adjacent infrequency. For example, for a 20 MHz system bandwidth with 100 PRBs, ifit is divided into 10 interlaces, then the k^(th) interlace is composedof the PRBs {k, k+10, k+20, . . . , k+90} and the (k+1)^(th) interlaceis composed of the PRBs {k+1, k+11, k+21, . . . , k+91}, 0<=k<=9. So thetwo interlaces, the k^(th) interlace and the (k+1)^(th) interlace areadjacent to each other and consecutive in frequency. Similarly, thek^(th) interlace and the (k−1)^(th) interlace are also adjacent to eachother and consecutive in frequency. In another example, two interlacesbeing adjacent in frequency may mean that all the PRBs of one interlace(e.g., PRB {x, y, z, and so forth}) that are uniformly spaced infrequency are adjacent to all the PRBs of another interlace (e.g.,PRB{x+/−1, y+/−1, z+/−1, and so forth}).

FIGS. 5 thorough 7 describe various embodiments for PUCCH channelstructure supporting multi-remote unit 102 multiplexing in oneinterlace.

Specifically, FIG. 5 illustrates one embodiment of a channel structure500 for multiplexing control information. The channel structure 500 maybe for PUCCH transmission on a LAA SCell and may be used to multiplexchannel information for up to 4 remote units 102 in one interlace. Thechannel structure 500 includes a subframe 502 having a first slot 504and a second slot 506. To create the channel structure 500, coded bits508 are input to a scrambler 510.

The scrambler 510 may scramble (e.g., transpose and/or invert) the codedbits 508 then output the scrambled coded bits to a QPSK modulator 512.After the QPSK modulator 512 modulates the scrambled coded bits, a firsthalf of symbols 514 are split from a second half of symbols 516.Orthogonal cover sequences w0 518, w1 520, w2 522, and w3 524 areapplied to the first half of symbols 514 and to the second half ofsymbols 516. The resulting signals use a discrete Fourier transform(“DFT”) 532 to convert a time domain signal into frequency componentsand an inverse fast Fourier transform (“IFFY') 534 to convert symbolsfrom the frequency domain to the time domain.

An orthogonal cover sequence is used in the time domain to differentiateremote units 102 and is applied per slot (e.g., the first slot 504 andthe second slot 506). Considering one-symbol duration may be reservedfor PUCCH LBT and another one symbol may be reserved for possible SRStransmission in same subframe, 6 symbols including DMRS (labeled “RS”)and data symbols (labeled “D”) per slot may be used for PUCCHtransmission. In the illustrated embodiment, the first symbol (e.g.,symbol 0 in the first slot 504) and/or the last symbol (e.g., symbol 6in the second slot 506) may be reserved for LBT or SRS. In each of thefirst slot 504 and the second slot 506, each of the two DMRS symbols isinserted between two consecutive data symbols to improve channelestimation performance. Because four symbols are available for data perslot, the channel structure 500 may support up to 4 remote units' PUCCHmultiplexed in one interlace in one subframe using four orthogonal coversequences {w0 518, w1 520, w2 522, w3 524} (e.g., {+1,+1,+1,+1}, {+1,−1,+1,−1}, {+1,+1,−1,−1}, {+1,−1,−1,+1}) used to differentiate differentremote units 102.

FIG. 6 illustrates another embodiment of a channel structure 600 formultiplexing control information. The channel structure 600 may be forPUCCH transmission on a LAA SCell and may be used to multiplex channelinformation for up to 8 remote units in one interlace. The channelstructure 600 includes a subframe 602 having a first slot 604 and asecond slot 606. To create the channel structure 600, coded bits 508 areinput to a scrambler 510.

The scrambler 510 may scramble (e.g., transpose and/or invert) the codedbits 508 then output the scrambled coded bits to a QPSK modulator 512.After the QPSK modulator 512 modulates the scrambled coded bits, symbols614 have orthogonal cover sequences w0 616, w1 618, w2 620, w3 622, w4624, w5 626, w6 628, and w7 630 applied thereto. The resulting signalsuse a DFT 532 to convert a time domain signal into frequency componentsand an IFFT 534 to convert symbols from the frequency domain to the timedomain.

An orthogonal cover sequence is used in the time domain to differentiateremote units 102 and is applied per the subframe 602. Accordingly, thecapacity in this embodiment is dependent on a number of data symbols perthe subframe 602. Considering that a total of two symbols are reservedfor LBT and/or possible SRS transmission in one subframe, 12 symbolsincluding DMRS (labeled “RS”) and data symbols (labeled “D”) persubframe are used for PUCCH transmission. In the illustrated embodiment,the first two symbols (e.g., symbols 0 and 1 in the first slot 604) arereserved for LBT and/or SRS. In each subframe 602, each of the four DMRSsymbols is inserted between two consecutive data symbols to improvechannel estimation performance. Because eight symbols are available fordata per subframe 602, the channel structure 600 may support up to 8remote units' PUCCH multiplexed in one interlace in one subframe usingeight orthogonal cover sequences {w0 616, w1 618, w2 620, w3 622, w4624, w5 626, w6 628, w7 6301 (e.g., {+1,+1,+1,+1,+1,+1,+1,+1},{+1,−1,+1,−1,+1,−1,+1,−1}, {+1,+1,+1,+1,−1,−1,−1,−1},{+1,+1,−1,−1,+1,+1,−1,−1}, {+1,−1,−1,+1,+1,−1,−1,+1},{−1,−1,+1,+1,−1,−1,+1,+1}, {−1,−1,−1,−1,+1,+1,+1,+1},{−1,+1,−1,+1,−1,+1,−1,+1}) used to differentiate different remote units102.

FIG. 7 illustrates a further embodiment of a channel structure 700 formultiplexing control information. The channel structure 700 may be forPUCCH transmission on a LAA SCell and may be used to multiplex channelinformation for up to 8 remote units in one interlace. The channelstructure 700 includes a subframe 702 having a first slot 704 and asecond slot 706. To create the channel structure 700, first coded bits708 are input to a first scrambler 708. The first scrambler 708 mayscramble (e.g., transpose and/or invert) the first coded bits 708 thenoutput the scrambled first coded bits to a first QPSK modulator 712.After the first QPSK modulator 712 modulates the scrambled coded bits,symbols 714 have orthogonal cover sequences w0 716, w1 718, w2 720, andw3 722 applied thereto. The resulting signals use a DFT 532 to convert atime domain signal into frequency components and an IFFT 534 to convertsymbols from the frequency domain to the time domain. Moreover, secondcoded bits 724 are input to a second scrambler 726. The second scrambler726 may scramble (e.g., transpose and/or invert) the second coded bits724 then output the scrambled second coded bits to a second QPSKmodulator 728. After the second QPSK modulator 728 modulates thescrambled coded bits, symbols 730 have orthogonal cover sequences w0716, w1 718, w2 720, and w3 722 applied thereto. The resulting signalsuse a DFT 532 to convert a time domain signal into frequency componentsand an IFFT 534 to convert symbols from the frequency domain to the timedomain.

An orthogonal cover sequence is used in the time domain to differentiateremote units 102 in one slot (e.g., the first slot 704 and the secondslot 706). One subframe 702 for PUCCH transmission is divided into twoslots and each slot may use one interlace for one PUCCH transmission, soeach subframe 702 may support two independent PUCCH transmissions.Considering the duration for PUCCH LBT may be limited in one symbol, 6symbols including DMRS (labeled “RS”) and data symbols (labeled “D”) perslot may be used for PUCCH transmission. In the illustrated embodiment,the first or last symbol in each slot may be reserved for LBT (e.g.,symbol 0 in the first slot 704 and symbol 0 in the second slot 706). Ineach of the first slot 704 and the second slot 706, each of the two DMRSsymbols may be inserted between two consecutive data symbols to improvechannel estimation performance. Because four symbols are available fordata per slot, the channel structure 700 may enable one slot to supportup to 4 remote units' PUCCH multiplexed in one interlace in one subframeusing four orthogonal cover sequences {w0 716, w1 718, w2 720, w3 722}(e.g.,{+1,+1,+1,+1}, {+1,−1,+1,−1}, {+1,+1,−1,−1}, {+1,−1,−1,+1}) usedto differentiate different remote units 102.

As explained in FIGS. 4 through 7, a dynamic carrier indication may beprovided to remote units 102 for PUCCH transmission in one carrier formultiple remote units 102, a common interlace indication may be providedto remote units 102 for B-IFDMA based PUCCH transmission an orthogonalcover sequence indication may be provided to remote units 102 formulti-remote unit 102 multiplexing in one subframe, a common HARQ timingindication may be provided to remote units 102 for all the remote units102 scheduled in one subframe and/or all the subframes within one DLburst for a remote unit 102, multiple PUCCH/PUSCH multiplexing in onesubframe may be enabled by a common LBT, and/or various PUCCH channelstructures may be used.

FIG. 8 is a schematic flow chart diagram illustrating one embodiment ofa method 800 for carrier determination. In some embodiments, the method800 is performed by an apparatus, such as the base unit 104. In certainembodiments, the method 800 may be performed by a processor executingprogram code, for example, a microcontroller, a microprocessor, a CPU, aGPU, an auxiliary processing unit, a FPGA, or the like.

The method 800 may include determining 802 a first carrier of multiplecarriers for a first device to transmit control information. In someembodiments, the method 800 may determine 802 the first carrier based onat least one of a load condition and an interference condition on themultiple carriers. The method 800 may also include transmitting 804, tothe first device, a first physical control signal indicating the firstcarrier and an interlace index. In some embodiments, the first physicalcontrol signal further indicates an orthogonal cover sequence index tothe first device. In various embodiments, the first physical controlsignal may indicate the first carrier, the interlace index, and theorthogonal cover sequence index. In some embodiments, the method 800 maytransmit the first physical control signal to a second device, and themethod 800 may receive control information from the second device on thefirst carrier. In such embodiments, the first physical control signalmay indicate the first carrier, an interlace index, and/or an orthogonalcover sequence index. The method 800 may include receiving 806 controlinformation from the first device on the first carrier.

In one embodiment, the method 800 determines a control channel for thefirst device. The control channel may be defined by at least one of aninterlace index and an orthogonal cover sequence index. In such anembodiment, the method 800 may transmit, to the first device, a secondphysical control signal indicating the control channel and the method800 may receive control information from the first device using thecontrol channel. In some embodiments, the method 800 may determine atime for the first device to transmit control information, transmit, tothe first device, a third physical control signal indicating thedetermined time, and receive control information from the first deviceduring the determined time. In certain embodiments, the method 800 maytransmit the third physical control signal to a second device, andreceive control information from the second device during the determinedtime. In some embodiments, the third physical control signal indicates adelay after the end of a transmission burst.

In certain embodiments, the method 800 may determine a random backoffcounter for the first device, and transmit, to the first device, afourth physical control signal indicating the random backoff counter. Invarious embodiments, the method 800 may transmit, to a second device,the fourth physical control signal.

FIG. 9 is a schematic flow chart diagram illustrating another embodimentof a method 900 for carrier determination. In some embodiments, themethod 900 is performed by an apparatus, such as the remote unit 102. Incertain embodiments, the method 900 may be performed by a processorexecuting program code, for example, a microcontroller, amicroprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, orthe like.

The method 900 may include receiving 902 a first physical control signalindicating a first carrier of multiple carriers for transmitting controlinformation and an interlace index. In various embodiments, the firstphysical control signal further indicates an orthogonal cover sequenceindex for transmitting control information. In certain embodiments, thefirst physical control signal may indicate the first carrier, theinterlace index, and the orthogonal cover sequence index. The method 900may also include transmitting 904 control information on the firstcarrier. In some embodiments, the method 900 may include transmitting904 control information on the first carrier using the interlace index.

In some embodiments, the method 900 includes receiving a second physicalcontrol signal indicating a control channel. The control channel may bedefined by at least one of an interlace index and an orthogonal coversequence index. In such embodiments, the method 900 includestransmitting control information using the control channel. In certainembodiments, the method 900 includes receiving a third physical controlsignal indicating a time, and transmitting control information duringthe time.

In some embodiments, the third physical control signal indicates a delayafter the end of a transmission burst. In certain embodiments, themethod 900 includes receiving a fourth physical control signalindicating a random backoff counter, and performing LBT using the randombackoff counter on the first carrier.

Embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. An apparatus comprising: a processor thatdetermines a first carrier of a plurality of carriers for a first deviceto transmit control information; a transmitter that transmits, to thefirst device, a first physical control signal indicating the firstcarrier, wherein the first physical control signal further indicates aninterlace index to the first device; and a receiver that receivescontrol information from the first device on the first carrier.
 2. Theapparatus of claim 1, wherein the first physical control signal furtherindicates an orthogonal cover sequence index to the first device.
 3. Theapparatus of claim 1, wherein: the processor determines a controlchannel for the first device, wherein the control channel is defined byat least one of an interlace index and an orthogonal cover sequenceindex; the transmitter transmits, to the first device, a second physicalcontrol signal indicating the control channel; and the receiver receivescontrol information from the first device using the control channel. 4.The apparatus of claim 1, wherein: the transmitter transmits the firstphysical control signal to a second device; and the receiver receivescontrol information from the second device on the first carrier.
 5. Theapparatus of claim 1, wherein: the processor determines a time for thefirst device to transmit control information; the transmitter transmits,to the first device, a third physical control signal indicating thedetermined time; and the receiver receives control information from thefirst device during the determined time.
 6. The apparatus of claim 5,wherein: the transmitter transmits the third physical control signal toa second device; and the receiver receives control information from thesecond device during the determined time.
 7. The apparatus of claim 5,wherein the third physical control signal indicates a delay after theend of a transmission burst.
 8. The apparatus of claim 1, wherein: theprocessor determines a random backoff counter for the first device; andthe transmitter transmits, to the first device, a fourth physicalcontrol signal indicating the random backoff counter.
 9. The apparatusof claim 8, wherein the transmitter transmits, to a second device, thefourth physical control signal.
 10. The apparatus of claim 1, whereinthe processor determines the first carrier based on at least one of aload condition and an interference condition on the plurality ofcarriers.
 11. A method comprising: determining a first carrier of aplurality of carriers for a first device to transmit controlinformation; transmitting, to the first device, a first physical controlsignal indicating the first carrier, wherein the first physical controlsignal further indicates an interlace index to the first device; andreceiving control information from the first device on the firstcarrier.
 12. The method of claim 11, wherein the first physical controlsignal further indicates an orthogonal cover sequence index to the firstdevice.
 13. The method of claim 11, further comprising: determining acontrol channel for the first device, wherein the control channel isdefined by at least one of an interlace index and an orthogonal coversequence index; transmitting, to the first device, a second physicalcontrol signal indicating the control channel; and receiving controlinformation from the first device using the control channel.
 14. Themethod of claim 11, further comprising: transmitting the first physicalcontrol signal to a second device; and receiving control informationfrom the second device on the first carrier.
 15. The method of claim 11,further comprising: determining a time for the first device to transmitcontrol information; transmitting, to the first device, a third physicalcontrol signal indicating the determined time; and receiving controlinformation from the first device during the determined time.
 16. Themethod of claim 15, further comprising: transmitting the third physicalcontrol signal to a second device; and receiving control informationfrom the second device during the determined time.
 17. The method ofclaim 15, wherein the third physical control signal indicates a delayafter the end of a transmission burst.
 18. The method of claim 11,further comprising: determining a random backoff counter for the firstdevice; and transmitting, to the first device, a fourth physical controlsignal indicating the random backoff counter.
 19. The method of claim18, further comprising transmitting, to a second device, the fourthphysical control signal.
 20. The method of claim 11, further comprisingdetermining the first carrier based on at least one of a load conditionand an interference condition on the plurality of carriers.
 21. Anapparatus comprising: a receiver that receives a first physical controlsignal indicating a first carrier of a plurality of carriers fortransmitting control information, wherein the first physical controlsignal further indicates an interlace index for transmitting controlinformation; and a transmitter that transmits control information on thefirst carrier.
 22. The apparatus of claim 21, wherein the first physicalcontrol signal further indicates an orthogonal cover sequence index fortransmitting control information.
 23. The apparatus of claim 21,wherein: the receiver receives a second physical control signalindicating a control channel, wherein the control channel is defined byat least one of an interlace index and an orthogonal cover sequenceindex; and the transmitter transmits control information using thecontrol channel.
 24. The apparatus of claim 21, wherein: the receiverreceives a third physical control signal indicating a time; and thetransmitter transmits control information during the time.
 25. Theapparatus of claim 24, wherein the third physical control signalindicates a delay after the end of a transmission burst.
 26. Theapparatus of claim 21, further comprising a processor, wherein: thereceiver receives a fourth physical control signal indicating a randombackoff counter; and the processor performs listen-before-talk (“LBT”)using the random backoff counter on the first carrier.
 27. A methodcomprising: receiving a first physical control signal indicating a firstcarrier of a plurality of carriers for transmitting control information,wherein the first physical control signal further indicates an interlaceindex for transmitting control information; and transmitting controlinformation on the first carrier.
 28. The method of claim 27, whereinthe first physical control signal further indicates an orthogonal coversequence index for transmitting control information.
 29. The method ofclaim 27, further comprising: receiving a second physical control signalindicating a control channel, wherein the control channel is defined byat least one of an interlace index and an orthogonal cover sequenceindex; and transmitting control information using the control channel.30. The method of claim 27, further comprising: receiving a thirdphysical control signal indicating a time; and transmitting controlinformation during the time.
 31. The method of claim 30, wherein thethird physical control signal indicates a delay after the end of atransmission burst.
 32. The method of claim 27, further comprising:receiving a fourth physical control signal indicating a random backoffcounter; and performing listen-before-talk (“LBT”) using the randombackoff counter on the first carrier.